In work with typical proteins the template Start1.2.cara should be sufficient. However, in special cases the user may be working with a protein containing unusual amino acids or even with artificial polymers. In this case it becomes necessary to build custom ResidueTypes.
Step-by-step guide to making a ResidueType:
Case I. New ResidueType is similar to one in the template.
- If the new ResidueType is similar to an existing ResidueType, right-click on the existing ResidueType and select "duplicate ResidueType" NOTE: this feature is not yet included in Cara 1.5 - use the following workaround:
- Right-Click in the ResidueType explorer and select "Import ResidueType".
- select any repository derived from Start1.2.cara or Start1.2.cara itself.
- From the displayed list select the ResidueType most similar to the one you want to create and click OK.
- Enter the Short Name for the new ResidueType which must be unique.
- Right-Click on the new ResidueType and select "Rename".
- enter the full name of the new ResidueType.
- you cannot change the Letter of the new ResidueType within CARA (unfortunately) Do this by editing the repository.
- Enter then Name, Short name, and Letter abbreviation for the new residue. The "Short Name" must be unique (if you used above workaround then skip this step).
- Right-Click on the new ResidueType and select MoleculeViewer.
- Modify the new ResidueType to have the correct structure. See MoleculeViewer for how to do this.
- Right-Click on new ResidueType and select "set terminals". Usually these will be correct if the ResidueType you duplicated has the same N- and C-terminal atoms.
- Right-Click on new ResidueType and select "set SpinSystemType". Select the SpinSystemType appropriate for the new residue.
Case II. New ResidueType is unrelated to existing ResidueTypes.
- Right-click in ResidueType Explorer and select "New ResidueType".
- Enter Name, Short Name (unique), Letter of the new ResidueType.
- Open MoleculeViewer and create the new ResidueType.
- Close MoleculeViewer, Right-click on the new ResidueType and select "Set Terminals".
- Enter the name of the atoms which connect to the previous (Nterminal) and following (Cterminal) residue.
- If the new ResidueType is the first of its class, you will need to create a new SpinSystemType for the class. See Creating new SpinSystemType.
- After creating a SpinSystemType, define the SpinSystemType for the new ResidueType by Right-clicking on the new ResidueType and selecting "Set SpinSystemType". Select the appropriate SpinSystemType.
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